1. Field of the Invention
The present invention relates to an inkjet recording apparatus and a cleaning method, and more particularly, to a technology of cleaning an intermediate transfer body in an inkjet recording apparatus which uses the intermediate transfer body, whereby ink and foreign matter remaining on the intermediate transfer body are removed with reducing the cost of consumables or the like.
2. Description of the Related Art
There are inkjet recording apparatuses which use an intermediate transfer system in which an image is formed on an intermediate transfer body by means of ink ejected from a recording head, and then the image on the intermediate transfer body is transferred to a recording medium. In an intermediate transfer system, when printing a full face image in which an image is recorded onto the whole surface of the recording medium without leaving borders, the image is also formed to the outside of the region corresponding to the recording medium, and therefore ink may be left on the intermediate transfer body after transfer to the recording medium. Furthermore, it may also happen that ink is left on the intermediate transfer body rather than being transferred to the recording medium, due to insufficient pressing force during transfer, or the like. There is a possibility that the presence of residual ink of this kind may affect image quality, and therefore it is necessary to remove the residual ink from the intermediate transfer body before forming the next image. In general, the method of removing foreign matter from the intermediate transfer body uses a method where the foreign matter on the intermediate transfer body is wiped away by means of a wiping member, such as a blade or a web member, or a method where the intermediate transfer body is cleaned by using a cleaning solution.
Japanese Patent Application Publication No. 5-261903 discloses a transfer type of inkjet recording apparatus in which liquid on the surface of a transfer drum is moved to the end portions of the transfer drum via guide grooves provided in a spiral fashion about the outer circumference of the transfer drum, the liquid then being recovered into a recovery tank via grooves provided in the end portions of the drum.
Furthermore, Japanese Patent Application Publication No. 8-39828 discloses an inkjet recording apparatus comprising an inkjet recording device in which a blade member is provided to one side of the ink ejection section, at a position adjacent to the side face of the ink ejection section and separated by a small gap from same, and when cleaning of the ink ejection section is carried out by wiping the cleaning blade over the ink ejection section, the cleaning blade makes contact with the front tip portion of a plate member and ink or foreign matter attached to the cleaning blade is removed by the front tip portion of the plate member.
However, in a method which wipes an intermediate transfer body by means of a blade, foreign matter accumulates on the blade and it becomes necessary to recover the foreign matter attached to the blade and to clean the blade, at periodic intervals. The method described in Japanese Patent Application Publication No. 8-39828 is conceivable as a method of cleaning the blade, but Japanese Patent Application Publication No. 8-39828 makes no mention of a method for recovering foreign matter which has been removed from the blade, and there is a concern that foreign matter or ink accumulated on the plate member or in the gaps may fall onto the image, thereby degrading image quality. In particular, if using an ink which has become highly viscous due to evaporation of the solvent, or if using an ink which has an essential high viscosity, the ink is liable to remain on the front tip portion of the plate member, and possibilities, such as residual ink falling off onto the image and becoming reattached to the blade, can be envisaged.
In a method which wipes an intermediate transfer body by means of a web member, there is a possibility of increased costs since the web is a consumable item, and in a method which cleans the intermediate transfer body by means of a cleaning solution, it is necessary to recover the cleaning solution, and furthermore, the cleaning solution is also a consumable item.
Japanese Patent Application Publication No. 5-261903 states that the ink collected between a removal roller and a transfer drum is held by the edge portions of a guide groove, but if soiling is adhering to the removal roller or the transfer drum, or if an ink of high viscosity is being used, or if the rotational speed of the transfer drum is high in a case where high-speed printing is being carried out, or the like, then a situation may occur in which the ink is not held by the edge portions of the guide grooves and the solvent adheres to the transfer drum again. In other words, a portion of the ink in the state of a meniscus formed between the removal roller and the transfer roller passes beyond the removal roller and remains on the transfer drum, and this may give rise to degradation of the image quality by mixing with subsequently ejected droplets of ink.